Gold-on-glass microwave split-ring resonators with PDMS microchannels for differential measurement in microfluidic sensing

Abstract

This paper describes a microwave resonator incorporating microfluidic lab-on-chip sensor system capable of performing simultaneous differential measurement based sensing of liquid samples. The resonators are split-ring resonator shapes made of gold on glass substrates. Directly bonded on glass substrates are polydimethylsiloxane microchannels. Sensor system design incorporates a pair of identical resonators, one of which performs reference reading from the background. Tracking the difference of the responses of both resonators simultaneously, rather than a single one, is used to obtain a more linear and noise-free reading. The sensor system was produced with conventional fabrication techniques. It is compatible with low-cost, simple, easy to handle sensing applications. Results indicate that reliable differential measurement was possible owing to a well-matched pair of sensors with a response error as low as 0.1%. It was also demonstrated that differential measurement capability enables sensing with improved linearity. Measurements were performed with glucose solutions in the range of 3.2-16.1 mM, achieving a sensitivity of 0.16 MHz/mM.

An Embroidered Slot-loaded Patch Antenna for Characterization of Dielectric Materials

“…If the geometry of the structure does not change, then the changes in the environment can be sensed if they alter the effective electrical permittivity or magnetic permeability of the structures. Several applications including measurement of biomolecular interactions [16,17], concentration of target solutions [18,19], and material characterization [13,20] have been demonstrated so far. The resolution of the measurement based on tracking the resonant frequency is determined by the quality factor for these applications.…”

RFID-Based Microwave Biosensor for Non-Contact Detection of Glucose Solution

“…Analytical models are developed in this work linking the RLC quantities to the geometry parameters of the CSRR. Following these models, the resonant frequency f 0 and Q factor of the CSRR can be derived based on the below equations [ 22 ]: …”

“…The Tag was fabricated through a Ti/Au (20/80 nm) sputtering process followed by a Cu (5 μm) plating process and made on a 0.8 mm glass substrate (SCHOTT B 270). The usage of a glass substrate can not only lower the cost but also reduce the dielectric loss of the substrate [ 22 ]. The microchannel was made of PDMS because of its good biological properties and metal compatibility.…”

Microwave Planar Resonant Solutions for Glucose Concentration Sensing: A Systematic Review

“…Single SRR configurations have been proposed with an extended capacitive gap [115], with an enzyme coating [91,96], with a microfluidic configuration measuring physiological glucose concentrations in water [116], with a CSRR-loaded square patch configuration [22,110,[117][118][119][120], with a defected ground design for measuring physiological concentrations in blood plasma samples [98] or with an RF tag configuration able to measure physiological concentrations in phantom interstitial fluid [121] (Figure 3a). A double SRR on a gold-on-glass substrate was proposed in [122], able to measure physiological concentrations of glucose in water with a differential configuration. A structure based on open SRR was tested for microfluidic measurement [123].…”